IllumOS distros use OpenZFS as well. Unless there is a new feature flag that has not been integrated yet, FreeBSD should be able to receive from them.
rsync is therefor most likely talking about commercial Solaris with zpool versions beyond 28.
Ah, I did not know that; I assumed IllumOS had the same ZFS as Solaris since they share a common ancestor and ZFS was in Solaris when it became OpenSolaris.
"rsync is therefor most likely talking about commercial Solaris with zpool versions beyond 28."